There was a time when I thought I was approaching a species of twelve-tone music. Yet even in works of that period the absolute tonal foundation is unmistakable.

Our peasant music, naturally, is invariably tonal, if not always in the sense that the inflexible major and minor system is tonal. (An "atonal" folk-music, in my opinion, is unthinkable.) Since we depend upon a tonal basis of this kind in our creative work, it is quite self-evident that our works are quite pronouncedly tonal in type. I must admit, however, that there was a time when I thought I was approaching a species of twelve-tone music. Yet even in works of that period the absolute tonal foundation is unmistakable.

By the time of his Fourth String Quartet, inversional symmetry had become as fundamental a premise of Bartók's harmonic language as it is of the twelve-tone music of Schoenberg, Berg, and Webern. Neither he nor they ever realized that this connection establishes a profound affinity between them in spite of the stylistic features that so obviously distinguish his music from theirs … Nowhere does he recognize the communality of his harmonic language with that of the twelve-tone composers that is implied in their shared premise of the harmonic equivalence of inversionally symmetrical pitch-class relations.